Drawing compass having a lengthening device of legs



Aug. 7, 1928s 7 3,68%194 K. AKASHI DRAWING COMPASS HAVING A LENGTHENING DEVICE 0F LEGS Filed July 16, 1923 OM VZM Patented 'Aug. 7, 1928.

tast er (Mum! G aft KAZUE AKASHI, OF TOKYO, JAPAN.

DRAWIN COMPASS HAVING A LENGTHENING DEVICE F LEGS.

Application filed July 16, 1923. Serial No. 651,881.

This invention relates to a drawing compass having a lengthening device and including a pin-leg of uniform cross-section throughout its length, a pin-leg extension of the same cross-section, and a longitudinally split connecting piece adapted to be telescopically fitted on said leg and extension and adjustably secured to said parts by means of set screws or the like. The object of the invention is to facilitate the adjustment of the length of the pin-leg of the compass so as to provide an instrument capable of drawing circles of very large diameter without the necessity of the operator holding tightly to the pin-leg and the pen or pencil leg.

In the accompanying drawings:

Fig. 1 is a view of adrawing compass provided with an extension member and a pin leg extension according to my invention.

Fig. 2 is a perspective View of the extension member.

Fig. 3 is an enlarged view of the pin leg end of Fig. 1. V i Fig. 4. is a sectional View of Fig. 3.

Fig. 5 is a side view of the pin leg extension for use with the arrangement shown in Fi .1.

Fig. 6 is a view of said extension taken at right angles to Fig. 5.

Fig. 7 is a section on the line 1-1 of Fig. 1. i

Sometimes a drawing compass must serve to draw a greater circle than that which can be drawn by normalhandling of the compass. In this case, a lengthening bar is adapted for a pencil or pen leg to increase its length. However, when the pencil or pen point is a long distance from a handle, it results that the turning moment applied on a grasping handle becomes great and this makes the driving of the point diflicult. Therefore, a draftsman or user is obliged to draw a circle holding the pencil or pen leg and pin leg respectively by each hand. Under such manner, the motion of both hands of the user is not only disadvantageous, but also time spent in drawing is great due to the slow traveling of the pencil or pen point. For eliminating these disadvantages, a lengthening bar must be applied to the pin leg. However, the pin leg of a compass of known construction is not capable of direct connection to the lengthening piece.

My invention is aimed to eliminate the along line 2 2 above mentioned design which will hereafter.

Fig. 1 shows an improved drawing compass with the cross section adapted for the object of the invention, and in which a pin leg 2 has an uniform cross section, for instance, a circular section, throughout its length, a lengthening piece of the same cross sectional form as that of the pin leg 2, but preferably shorter than the latter. Fig. 2 shows a connecting piece which is constructed from a metallic tube provided with a longitudinal slit 9. This tube may connect the pin leg 2 and the lengthening leg 10 telescopically for permitting adjustment of the pin leg as shown in Fig. 1. When it is required to draw a circle larger than can be drawn by the drawing compass without the extension member, the split extension 8 and the pin leg extension 10 are utilized. When. a clamping nut 12 engaged in a set screw 11 attached to the lengthening leg, is unscrewed, the connecting piece can be brought into engagement with pin leg extension 10. After the connecting piece 8 is mounted on to the pin leg extension 10, the nut 19. is clamped at any desired position. Then the nut G is also unscrewed and the pin holder 3 is put in alignment with the leg to make the free end of the pin leg 2 readily insertible into the other end of the connecting piece 8 and is again clamped at a desired aosition.

A pin holder 3 is of less wldth than the pin leg 2. Therefore, no obstruction is encountered during insertion, if the pin a is put into alignment with the leg 2.

As shown in F 1 the distance between the handle 1 and the pen or pencil point 7, which is secured to the other leg of the compass, that is, the drawing instrument leg, is comparatively less than the corresponding distancei. e. a distance between the handle and pen or pencil point 15-of the ordinary drawing compass as shown in Fig. 5. The distance between the pencil or pen point 7 and pin point 15 may be now easily regulated through a wide range because the position through the connecting range relative to the pin leg 10 or to the pin leg 2 may be changed.

Having now described and ascertained the nature of this invention and in what manner the same is to be performed, I declare that what I claim is A drawing compass including a pin leg and a drawing instrument leg pivotally condisadvantages by special be more fully described are neeted together said pin leg being of uniform cross sectlon throughout substantially its entire length, a split extension member tubular throughout its length and slidably mounted on the pin leg, a' pin leg extension of the same cross section as the pin leg, eX- tending into the tubular member and adjustable axially relatively to the latter, and

screws engaging the pin leg'anol pin (leg extension extending through the split and the tubular member and adjustably clamping the tubular member ,to the pin leg and the pin leg extension.

-In testimony whereof he faffixes his signature. v g V KAZUE AKASHI. 

